New high-occupancy lanes on Melbourne's roads and incentives for more government workers to leave their cars at home are two options being pursued by the State Government to reduce city congestion.

Fiona Macrae, spokeswoman for Roads Minister Tim Pallas, said all government offices in central Melbourne were developing plans to "promote travel to work by walking, cycling and public transport, as well as car-pooling and telecommuting".

She said an evaluation of the performance and efficiency of existing high-occupancy vehicle lanes had been completed and "guidelines for nominating future options for high-occupancy vehicle lanes" were being developed.

The moves follow recommendations in a report by the Victorian Competition and Efficiency Commission last year that examined ways to manage congestion.

Also, the Victorian Government has begun offering "early bird" free public transport fares on some train lines to entice more people to use public transport outside of peak periods.

A Committee for Melbourne inquiry found that unless urgent action was taken, the city's booming population would clog its streets.

The investigation found the cost of congestion in Melbourne would double from $4 billion annually to $8 billion by 2015. Peak travel speeds were projected to decline from 19.7km/h to 15.2km/h.